Stinky-smelling breath could be a sign you’re dehydrated, according to Dr. Ada S. Cooper, D.D.S., a national spokesperson for the American Dental Association. “Don’t think that living a life of mouth wash four times a day is always going to cure your bad breath,” she told Business Insider. “When your mouth becomes more dry, you have less saliva. And when you have less saliva, food and bacteria tends to sit in your mouth for a much longer period of time.”

Of course, there are other reasons for bad breath, beyond a simple dry mouth or poor hygiene. Dr. Cooper recommends always brushing your teeth at night, since trapped food and bacteria can produce an odor while you sleep. If your bad breath sticks around, a dentist might need to help you uncover the root cause of your halitosis.